11 Gb/s 140 GHz OOK modulator with 24.6 dB isolation utilising cascaded switch and amplifier‐based stages in 65 nm bulk CMOS

This study presents a complementary metal–oxide–semiconductor (CMOS) 140 GHz on–off‐keying (OOK) modulator with high isolation and low ON‐state insertion loss based on a cascaded architecture of a switch‐based and amplifier‐based modulators. A prototype implemented in a 65 nm bulk CMOS process operates at 140 GHz carrier input and realises 24.6 dB isolation, whereas in ON‐state it achieves 0.3 dB gain and −0.2 dBm OP1 dB with 8 mW power consumption. Up to 11 Gb/s modulation is verified with the spectrum and demodulated waveform measurements. The proposed OOK modulator occupies the core area of 250×380 μm 2 .